The mygalomorph spider family Theraphosidae is represented by 980 species in 144 genera
globally (World Spider Catalogue 2018). Within the family Theraphosidae sites the genus
Chilobrachys. The genus Chilobrachys is found in South and East Asia, with 27 described species
to date (World Spider Catalogue 2018). They are ground dwelling spiders, living in burrows
lined with silk and other debris (Nanayakkara, 2013, Nanayakkara 2014b). In Sri Lanka the
genus is represented by only one species, namely Nanayakkara 2014b), which also happens to be
the type species (species typica) for the genus.

The arboreal spiders in the genus Poecilotheria is represented by 16 species and restricted to India and Sri Lanka. Each country has eight endemic species. During a survey on mygalomorph spiders in the Northern Province of Sri Lanka, the critically endangered species of Theraphosidae Poecilotheria hanumavilasumica was discovered for the first time outside of its native habitat in India, expanding its range to northern Sri Lanka. The discovery of P. hanumavilasumica is unique, as it used to be a critically endangered and endemic species of the genus Poecilotheria found in India, and it is evident that during the land bridge connection between India and Sri Lanka, when the Pleistocene epoch biotic exchange took place between the two countries, taxa were dispersed through the land connections.